3D displays have taken many forms, such as parallax panoramagrams which use lenticular display elements (“lenticules”) or parallax barriers to spatially demultiplex and steer light from an image surface to one or more viewing regions. Lenticules may be bi-convex, and may alternatively be long, thin lenses having a flat surface on one side and an opposing curved surface which forms a plano-convex lens. When viewed, the lenticule may provide a view angle-dependant striped or sliced portion of an image positioned behind each lenticule, i.e., the slice that is viewable is dependent upon the angle from which the viewer views the image. Therefore, arrays of lenticules can be used to create a parallax effect wherein different views or slices of total images are apparent from different viewing angles. In this way, a 3D effect can be achieved if the components of a 3D image are successfully rendered as separate slices, presented at the image surface as spatially multiplexed views, and are viewed through a lenticular array in a parallax manner.
The lenticular array concept has been used to create “no 3D glasses required” or “autostereoscopic” displays which uses a sheet array of lenticular lenses to steer interdigitated left, intermediate, and right eye views to a properly positioned observer.
Lenticular 3D displays techniques deserve their own category because they have earned a competitive place in the commercial market. However, the number of views they are capable of displaying is usually limited because they employ spatial multiplexing, whereby the resolution of the display is sacrificed to include parallax information. The minimum pixel size is consequently a limiting factor in these displays.
Interactive electronic flat panel 3D displays have been developed based on these techniques.
For example, StereoGraphics Corporation (San Rafael, Calif.) sells the SynthaGramm flat panel monitor series which is a lenticular-based 3D display. The SynthaGram series ranges from XGA (1024×768 pixel) to UXGA (3840×2400 pixel) monitors, and employs a custom fabricated diagonal lenticular screen which divides pixels into 9 different views. The monitor is driven by the DVI data output of a graphics card. The lenticular screen is designed to eliminate moire fringing, which can occur in lenticular flat panel screens, and divides pixels on the RGB level.
The drawback of existing lenticular 3D displays, and all spatially-multiplexed multi-view 3-D displays, is that by definition they trade off the projector's spatial resolution for the number of views displayed. The number of views is also limited by the shape of the lenticular elements and the pixel size. To date lenticular displays have produced at most 12 views.
Therefore, a 3D scanning system and or display which produces more views is needed.
It should be noted that references to the term “lenticular” should be interpreted to include other methods of using spatial multiplexing to encode two or more views of a 3-D scene into a single 2-D field of pixels. These “panoramagrams” or “parallax displays” can use many optical devices to perform demultiplexing, such as lenticular sheets, parallax barriers, fly's-eye lens arrays, or holographic optical elements. This invention employs lenticulars in a time-multiplexed rather than or in addition to a spatially-multiplexed manner as described below.